Effects of In-Plane π’ Bonding on Electronic Transition Energies for Inorganic Polymers

1989 ◽  
Vol 173 ◽  
Author(s):  
Kim F. Ferris ◽  
Steven M. Risser ◽  
Angela K. Hanson
Keyword(s):  
Electronic Structure ◽  
Optical Transition ◽  
Inorganic Polymers ◽  
Contour Analysis ◽  
Bond Polarity ◽  
Polymeric Systems ◽  
Transition Energies ◽  
Vertical Ionization Energy ◽  
Semi Empirical ◽  
Electronic Transition Energies

ABSTRACTThe electronic structure of organic and inorganic polymeric systems are well described in terms of their molecular symmetry, even with the large bond polarity shown by such systems as polyphosphazenes. We have performed calculations using the semi-empirical CNDO/1 method to determine the valence electronic structure for a series of model phosphonitrilic and organic compounds. The optical transition energies for phosphonitrilic compounds are greater than their organic counterparts as a result of in-plane π’ bonding interactions. The extent of these interactions is modulated by the electronegativity of the substituent groups on the phosphorus atoms. We report values for the vertical ionization energy and electronic absorption wavelengths, and use molecular orbital contour analysis to show the effects of ligand electronegativity on the π’ network.

Electronic structure and optical transition energies of theUcenter in alkaline-earth fluorides

1978 ◽  
Vol 18 (4) ◽  
pp. 1977-1985 ◽  
Author(s):  
L. E. Oliveira ◽  
B. Maffeo ◽  
H. S. Brandi ◽  
M. L. de Siqueira
Keyword(s):  
Electronic Structure ◽  
Alkaline Earth ◽  
Optical Transition ◽  
Transition Energies

A Semi-empirical Analysis of the Electronic Spectrum and Molecular Structure of Formaldehyde

1972 ◽  
Vol 50 (5) ◽  
pp. 646-652 ◽  
Author(s):  
I. Absar ◽  
C. S. Lin ◽  
K. L. McEwen
Keyword(s):  
Molecular Structure ◽  
Molecular Orbital ◽  
Electronic Transitions ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Matrix Elements ◽  
Transition Energies ◽  
Relative Separation ◽  
Semi Empirical ◽  
Electronic Transition Energies

The electronic transition energies and ionization potentials of formaldehyde have been calculated by a semi-empirical molecular orbital method, using several different ways of evaluating the diagonal matrix elements, in an attempt to adapt the Pariser–Parr–Pople method to the calculation of σ electron properties. The use of theoretically computed penetration integrals in this semi-empirical calculation lead to incorrect relative separation of the π-, σ-, and nonbonding molecular orbital energies, and hence to failure in predicting n →π* and n → σ* transition energies. A method is developed which reproduces the spectrum of formaldehyde (which includes n–π*, π–π*, and n–σ* electronic transitions) satisfactorily. In paper II of this series, this method is applied to study the spectrum of HCN and CO2.

Experimental and Computational Studies on the Electronic Spectral properties of Some 3-Hydroxy, 4-Arylazo [(Benzylidene) Dithio] Diacetic Acids

2003 ◽  
Vol 2003 (4) ◽  
pp. 188-190 ◽  
Author(s):  
Gamal A. Gohar
Keyword(s):  
Organic Solvent ◽  
Electronic Transition ◽  
Spectral Properties ◽  
Azo Compounds ◽  
Experimental Measurements ◽  
Computational Studies ◽  
Transition Energies ◽  
Solvent Parameters ◽  
Semi Empirical ◽  
Electronic Transition Energies

The correlations between the electronic spectral properties of the title azo compounds and organic solvent parameters have been analysed also, their electronic transition energies have been calculated, using a semi empirical approach and the results were compared with the experimental measurements.

A semi-empirical method for the calculation of the electronic structure of glass

1970 ◽  
Vol 2 (4) ◽  
pp. 865-874 ◽  
Author(s):  
I. V. Abarenkov ◽  
A. V. Amosov ◽  
V. F. Bratsev ◽  
D. M. Yudin
Keyword(s):  
Electronic Structure ◽  
Empirical Method ◽  
Semi Empirical

A semi-empirical molecular orbital scheme to study electron transfer in iron–sulphur proteins

2005 ◽  
Vol 33 (1) ◽  
pp. 20-21 ◽  
Author(s):  
M. Sundararajan ◽  
J.P. McNamara ◽  
M. Mohr ◽  
I.H. Hillier ◽  
H. Wang
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Molecular Orbital ◽  
Parametric Method ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Semi Empirical

We describe the use of the semi-empirical molecular orbital method PM3 (parametric method 3) to study the electronic structure of iron–sulphur proteins. We first develop appropriate parameters to describe models of the redox site of rubredoxins, followed by some preliminary calculations of multinuclear iron systems of relevance to hydrogenases.

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